Ubuntu 16.04 — postgresql-9.5 — multiple vulnerabilities (20 CVEs) — patch and remediation guide

📖 ~4 min read  •  Source: Ubuntu Security Notice USN-7358-1

Related CVEs: CVE-2024-10976 CVE-2024-10977 CVE-2024-10978 CVE-2024-10979 CVE-2024-7348 CVE-2024-0985 CVE-2023-5869 CVE-2023-5870  +12 more

Upstream summary: Wolfgang Walther discovered that PostgreSQL incorrectly tracked tables with
row security. A remote attacker could possibly use this issue to perform
forbidden reads and modifications. (CVE-2024-10976)

Jacob Champion discovered that PostgreSQL clients used untrusted server
error messages. An attacker that is able to intercept network
communications could possibly use this issue to inject error messages that
could be interpreted as valid query results. (CVE-2024-10977)

Tom La

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

postgresql-9.5 runs as a long-lived process on Ubuntu 16.04, started at boot and holding open sockets (visible in ss -lntp), so a flaw in it stays reachable for as long as the service is up. Exploitation usually means code execution in the daemon’s own security context, memory disclosure from a process holding credentials and cached client data, or a crash that takes the listener down. Workers started before the upgrade keep running the old binary until the unit is reloaded or restarted. postgresql-9.5 is a genuine long-running service, so restart steps do apply — but confirm the unit name first with systemctl list-unit-files | grep -i postgresql-9.5, since it often differs from the package name (bind ships named.service).

Environment & Reproduction

Reproduction targets Ubuntu 16.04 (xenial). Confirm release and installed package:

lsb_release -a
cat /etc/os-release
dpkg -l postgresql-9.5 | tail -2
apt-cache policy postgresql-9.5
uname -r

Exercise the workload that uses postgresql-9.5 while collecting:

sudo journalctl -u postgresql -b --no-pager | tail -200
sudo journalctl -xe --no-pager | tail -200
sudo tail -200 /var/log/apt/history.log
sudo tail -200 /var/log/kern.log | grep -i apparmor

Root Cause Analysis

Root cause is documented in Ubuntu Security Notice USN-7358-1. Canonical security maintainers shipped fixes in the corresponding postgresql-9.5 update for Ubuntu 16.04; running an outdated build leaves the host exposed to the failure modes described in the advisory. On this release the fix typically arrives via the Ubuntu Pro ESM (esm-infra / esm-apps) channels rather than the standard archive. Correlate apt history with the journal:

grep -A2 -B2 postgresql-9.5 /var/log/apt/history.log
zgrep -A2 -B2 postgresql-9.5 /var/log/apt/history.log.*.gz 2>/dev/null
cat /proc/sys/kernel/tainted   # non-zero = tainted kernel / out-of-tree modules

Quick Triage

Run these on Ubuntu 16.04 to capture the current state of postgresql-9.5:

dpkg -l postgresql-9.5 | tail -1                  # installed version
dpkg -V postgresql-9.5                             # verify shipped files
sudo apt update && apt list --upgradable 2>/dev/null | grep -i security
systemctl is-active postgresql
sudo ufw status verbose 2>/dev/null | head -20
sudo aa-status 2>/dev/null | head -20
# If postgresql-9.5 ships a service unit (unit/job name often differs from pkg name, e.g.
# bind9→named, apache2→apache2, postgresql-NN→postgresql@NN-main):
systemctl list-unit-files | grep -i postgresql | head

On xenial the standard archive no longer ships security fixes. Verify Ubuntu Pro ESM coverage:

# `pro` CLI not available on this release; check the older `ubuntu-advantage-tools`:
sudo ua status --format=json 2>/dev/null | head
apt-cache policy | grep -i esm

Step-by-Step Diagnosis

1. List failing services.

   systemctl --failed --no-pager

2. Tail the journal / syslog for postgresql-9.5.

   sudo journalctl -u postgresql -f --no-pager
   sudo journalctl -xe -f --no-pager

3. Inspect UFW (Uncomplicated Firewall) state.

   sudo ufw status numbered
   sudo ufw show added
   sudo iptables -L -n -v | head -30

4. Surface AppArmor denials and switch the profile to complain mode if needed.

   sudo journalctl -k 2>/dev/null | grep -i 'apparmor="DENIED"' | tail -30
   sudo aa-status
   # /etc/apparmor.d/usr.bin.postgresql-9.5 or usr.sbin.postgresql-9.5 — inspect first
   sudo aa-complain /etc/apparmor.d/usr.bin.postgresql-9.5 2>/dev/null || true

5. Verify postgresql-9.5 integrity and reinstall if anything is altered.

   sudo dpkg -V postgresql-9.5
   sudo debsums -c postgresql-9.5 2>/dev/null
   sudo apt install --reinstall -y postgresql-9.5

6. Correlate findings with /var/log/apt/history.log, /var/log/dpkg.log, and Ubuntu Security Notice USN-7358-1 to pin the change that introduced the regression.

Solution – Primary Fix

Apply the corrective apt transaction referenced by Ubuntu Security Notice USN-7358-1, then reload the affected service:

sudo apt update
sudo apt -y install --only-upgrade postgresql-9.5
sudo systemctl daemon-reload
# Service name may differ from pkg name; check first:
systemctl list-unit-files | grep -i postgresql | head
sudo systemctl restart postgresql
dpkg -l postgresql-9.5 | tail -1            # confirm new version
systemctl is-active postgresql

On xenial the standard archive is past EoL for security; enable Ubuntu Pro ESM to receive the fix:

# Older releases use the `ua` command:
sudo ua attach <token>
sudo ua enable esm-infra
sudo ua enable esm-apps
sudo apt update
sudo apt -y install --only-upgrade postgresql-9.5

For kernel / glibc / systemd / openssl advisories a reboot (or Livepatch) is required:

sudo apt install -y needrestart
sudo needrestart -r l       # list units that need restart
sudo systemctl reboot       # or: sudo shutdown -r now

Solution – Alternative Approaches

If the primary upgrade is not viable, pick from these:

• Hold the package so apt cannot upgrade it:

  sudo apt-mark hold postgresql-9.5
  apt-mark showhold | grep postgresql-9.5
  # Release the hold later with:
  sudo apt-mark unhold postgresql-9.5

• Pin a known-good version via apt preferences:

  # /etc/apt/preferences.d/postgresql-9.5.pref
  Package: postgresql-9.5
  Pin: version <good-version>
  Pin-Priority: 1001

• Downgrade to an older version if a regression is suspected:

  apt-cache madison postgresql-9.5
  sudo apt install --allow-downgrades -y postgresql-9.5=<older-version>

• Investigate AppArmor blocking the new binary; switch to complain briefly, capture denials, then re-enforce:

  sudo aa-complain /etc/apparmor.d/usr.bin.postgresql-9.5 2>/dev/null
  # reproduce the failure
  sudo journalctl -k | grep apparmor | tail
  sudo aa-enforce /etc/apparmor.d/usr.bin.postgresql-9.5 2>/dev/null

• Take only the security pocket update and defer the full point-release upgrade:

  sudo apt -y install --only-upgrade -t xenial-security postgresql-9.5

Verification & Acceptance Criteria

All of these should pass after the fix is applied:

dpkg -l postgresql-9.5 | tail -1                                  # expected fixed version
apt list --upgradable 2>/dev/null | grep -i security || echo OK
systemctl is-active postgresql
sudo journalctl -u postgresql --since "5 minutes ago" --no-pager | grep -iE "error|fail" || echo OK
sudo ufw status numbered | head
sudo aa-status 2>/dev/null | head -5

The conditions described in the advisory must no longer be reported for postgresql-9.5 across two consecutive runs.

Rollback Plan

Capture state before any change:

apt list --installed 2>/dev/null > /root/apt-pre.txt
dpkg --get-selections > /root/dpkg-pre.txt
# ZFS-on-root (Ubuntu 20.04+ default installer option):
sudo zfs snapshot rpool/ROOT/ubuntu@pre-postgresql-9-5
# LVM-on-root:
sudo lvcreate -L 4G -s -n root_pre_patch /dev/<vg>/<root-lv>

To revert:

sudo apt install --allow-downgrades -y postgresql-9.5=<old-version>
sudo systemctl daemon-reload
sudo systemctl restart postgresql
# Kernel rollback: pick the prior kernel from the GRUB menu, then:
sudo systemctl reboot
# ZFS rollback (rolls the whole root dataset):
sudo zfs rollback -r rpool/ROOT/ubuntu@pre-postgresql-9-5

Prevention & Hardening

Reduce the chance of this recurring on Ubuntu 16.04 (xenial):

• Enable scheduled security updates via unattended-upgrades:

  sudo apt install -y unattended-upgrades update-notifier-common
  sudo dpkg-reconfigure -plow unattended-upgrades
  # /etc/apt/apt.conf.d/50unattended-upgrades:
  Unattended-Upgrade::Allowed-Origins { "${distro_id}:${distro_codename}-security"; };

• Install needrestart so services restart automatically after library upgrades:

  sudo apt install -y needrestart
  # /etc/needrestart/needrestart.conf -> $nrconf{restart} = 'a';

• Attach Ubuntu Pro for ESM (mandatory on this past-EoL release) and Livepatch where supported:

  sudo ua attach <token>
  sudo ua enable esm-infra
  sudo ua enable esm-apps

• Subscribe to ubuntu-security-announce and watch ubuntu.com/security/cves.

• Monitor file integrity with debsums and AIDE:

  sudo apt install -y debsums aide
  sudo debsums -ca
  sudo aideinit && sudo mv /var/lib/aide/aide.db.new /var/lib/aide/aide.db
  sudo aide --check

• For estate-wide patching, manage with Canonical Landscape:

  sudo apt install -y landscape-client
  sudo landscape-config

• Keep AppArmor profiles in enforce mode and apply CIS Ubuntu Linux Benchmark hardening.

Related Errors & Cross-Refs

Issues that commonly surface alongside a postgresql-9.5 update: apt lock contention, broken dpkg state, systemd ordering cycles, AppArmor denials, and UFW rule drift. Useful triage:

sudo dpkg --configure -a
sudo apt --fix-broken install
systemd-analyze critical-chain
sudo journalctl -k 2>/dev/null | grep -i apparmor | tail
cat /proc/sys/kernel/tainted

View all ubuntu-16-04 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Primary reference: Ubuntu Security Notice USN-7358-1. Manual pages useful on Ubuntu 16.04:

man apt
man apt-get
man apt-mark
man dpkg
man systemctl
man journalctl
man ufw
man apparmor
man aa-status
man unattended-upgrades
man ua

Other resources: Ubuntu Security Notices, Ubuntu CVE Tracker, Ubuntu upgrade notes, and per-package notes in /usr/share/doc/postgresql-9.5/ for components implicated in this advisory.